"The Blue Danube" is the common English title of "An der schönen blauen Donau", Op. 314 (German for "By the Beautiful Blue Danube"), a waltz by the Austrian composer Johann Strauss II, composed in 1866. Originally performed on 15 February 1867 at a concert of the Wiener Männergesang-Verein (Vienna Men's Choral Association).

The waltz soon became a secret anthem of Austria and is regularly played at the turn of the year.